Steam Tracing

Many companies show a dotted line alongside a pipeline on the P&ID to indicate heat tracing. It is also the norm to show the pipe as lagged. If lagging is present, only one trace is required. The rest can be dealt with inside the local Piping Standard and the local Specification that are issued to the Contractor as paart of the tendering process.

Thanks for your reply.

Right now our client is asking for detail installation drawings for steam tracing apart from the dotted line along with main line in P&ID and isometric drawing. Does any body have any idea how to do it

One way is to find someone (possibly a tradesman (or woman)) who knows how to properly install steam tracing (i.e., can do it with their own hands), then pick their brain and create a drawing accordingly. Or, find a designer, draftsman, or consultant who has done that before. Here are some of the things I think you'd need to consider:

• I presume there will be some sort of control valve to control the steam, possibly block and bypass valves to allow maintenance on that control valve, possibly one or more temperature (or other) sensors, a need to tap a source of steam somewhere, a need to do something with the return flow (dump it to drain, return it to a boiler or tank).

• Possibly multiple (and varying) loops for different process pipes
  

• I guess lagging (which somebody mentioned) is what I might call insulation, presumably somebody has to specify the thickness of the lagging.
  

• Maybe some "general detail" of the steam tracing itself--maybe so many wraps per foot (does steam tracing wrap around a pipe like electrical heat tracing would, or is it just installed parallel to and in contact with the process pipe?), or maybe how many tubes run "next to" each process pipe, maybe varying based on pipe size and "duty".
  

• A typical method of fastening the steam tracing to the process pipe, (presumably this all goes on before the lagging--so say that somewhere, and maybe the lagging and its fastening holds the steam tracing on the process pipe.

• Maybe some details or notes about what to do at fittings (angle, Y, T, ...) and valves.

Also, I'd talk to the client / final owner of the facility and his engineer--see if they have any special requirements. Especially if this work is done in an existing plant, their maintenance department has probably learned (the hard way) about special requirements.

It is exceptional to ask for this level of detail at the Client level. His "Approved for construction" isue P&ID and Piping Standards are all the contractor usually needs to work to.

A small cross-sectional detail drawing might help, perhaps showing a single steam trace line at 6:00 (along bottom of the main pipe), or two lines at 4:30 and 7:30 (or whatever), and lagging (insulation). On the main drawing, flag it with a label like "See detail A6 with notes." The notes with the detail can specify line sizes, insulation type and thickness, etc. The steam trace line is likely to expand/contract more than the main pipe, so allowance must be made for it to slip.